RAND_bytes(3) OpenSSL RAND_bytes(3)NAME
RAND_bytes, RAND_pseudo_bytes - generate random data
SYNOPSIS
#include <openssl/rand.h>
int RAND_bytes(unsigned char *buf, int num);
int RAND_pseudo_bytes(unsigned char *buf, int num);
DESCRIPTIONRAND_bytes() puts num cryptographically strong pseudo-random bytes into
buf. An error occurs if the PRNG has not been seeded with enough ran‐
domness to ensure an unpredictable byte sequence.
RAND_pseudo_bytes() puts num pseudo-random bytes into buf. Pseudo-ran‐
dom byte sequences generated by RAND_pseudo_bytes() will be unique if
they are of sufficient length, but are not necessarily unpredictable.
They can be used for non-cryptographic purposes and for certain pur‐
poses in cryptographic protocols, but usually not for key generation
etc.
RETURN VALUESRAND_bytes() returns 1 on success, 0 otherwise. The error code can be
obtained by ERR_get_error(3). RAND_pseudo_bytes() returns 1 if the
bytes generated are cryptographically strong, 0 otherwise. Both func‐
tions return -1 if they are not supported by the current RAND method.
SEE ALSOrand(3), ERR_get_error(3), RAND_add(3)HISTORYRAND_bytes() is available in all versions of SSLeay and OpenSSL. It
has a return value since OpenSSL 0.9.5. RAND_pseudo_bytes() was added
in OpenSSL 0.9.5.
0.9.7d 2003-11-20 RAND_bytes(3)